Semiconductor components, such as dice and packages, are tested at the wafer level prior to being singulated into separate components, and then at the die level prior to shipment. For certifying a component as a known good die (KGD), the component must also be burn-in tested. Burn-in tests are typically performed by placing a singulated component in a test socket on a burn-in board. The burn-in board mounts to an oven in electrical communication with test circuitry. The test socket provides electrical connections for addressing the integrated circuits on the component, while the component is subjected to elevated temperatures for an extended period of time.
The test socket includes contacts for electrically engaging the terminal contacts on the component. For example, the terminal contacts on the component can comprise bumps, balls, or leads, and the socket contacts can comprise springs, pins or beams. One type of test socket includes a nest which functions to align the component in the socket, such that the socket contacts electrically engage the terminal contacts on the component.
As the industry advances, semiconductor manufacturers are developing new components having smaller peripheral outlines (footprints), and denser configurations of terminal contacts. For example, a second generation component, such as a chip scale package (CSP), typically has a smaller outline than a first generation component, such as a ball grid array (BGA) device. These differences in size require that the test sockets be modified to accommodate the later generation components. For example, the nest in a test socket can be replaced by a different nest configured to align the second generation component in the test socket. With some prior art test sockets it is difficult to replace the nest in the field without damaging or stressing other elements of the test socket, particularly the socket contacts.
Referring to FIGS. 1A–1B and 2A–2B, a prior art burn-in test socket 10 configured to electrically engage a semiconductor component 12 (FIG. 2A) having a pattern of terminal contacts 14 (FIG. 2A) is illustrated. In this example the component 12 comprises a chip scale semiconductor package, and the terminal contacts 14 comprise solder bumps, or balls, in an area array (e.g., ball grid array). The test socket 10 includes a base 16 (FIGS. 1A and 2A), a movable lid 18 (FIGS. 1A–1B and 2A–B) and a nest 20 (FIGS. 1B and 2B).
The base 16 includes four cylindrical mounting pins 22 (FIGS. 1A and 2A) configured for mounting the test socket 10 to a burn-in board (not shown) having mating circular openings (not shown) for engaging the mounting pins 22. The base 16 also includes a plurality of pin contacts 24 (FIGS. 1A and 2A) configured to electrically engage mating contacts (not shown) on the burn-in board. The base 16 also includes a contact plate 26 (FIGS. 1B and 2B) having a checker board pattern of generally rectangular openings 28 (FIGS. 1B and 2B), that correspond in size and location to the terminal contacts 14 on the component 12. In addition, selected openings 28 on the contact plate 26 include socket contacts 30 (FIGS. 2A and 2B) in electrical communication with the pin contacts 24 (FIG. 1A), which are configured to electrically engage the terminal contacts 14 on the component 12.
The lid 18 is movably mounted to the base 16, and operates a pair of retention mechanisms 32 configured to retain the component 12 on the contact plate 26. The retention mechanisms 32 comprise latches that contact the top of the component 12 proximate to opposing longitudinal edges thereof to hold the component 12 on the contact plate 26. Springs 34 (FIG. 1A) on the base 16 bias the lid 18 and the retention mechanisms 32 to a testing position shown in FIGS. 1A and 2A, in which the component 12 is retained on the contact plate 26 with the terminal contacts 14 (FIGS. 2A and 2B) in electrical communication with the socket contacts 30 (FIGS. 2A and 2B). In FIGS. 1A and 1B, the socket 10 is shown in the testing position, but without the component 12 having been loaded into the socket 10.
Compression of the lid 18 to the loading/unloading position shown in FIGS. 2A and 2B, operates the retention mechanisms 32, such that the component 12 can be loaded into the test socket 10 without interference from the retention mechanisms 32. Also in the loading/unloading position, the location of the contact plate 26 is shifted such that the terminal contacts 14 on the component 12 can enter the openings 28 on the contact plate 26 without interference from the socket contacts 30.
Referring to FIGS. 3A–3C and 4, the nest 20 is shown separately, after having been removed from the test socket 10. The nest 20 functions as an alignment member for aligning the component 12 in the test socket 10. In addition, the nest 20 can be removed from the test socket 10, and replaced by a second nest (not shown) configured to align a different component (not shown) in the test socket 10.
The nest 20 has a peripheral outline that matches the outline of a hollow interior portion 36 (FIG. 2B) of the test socket 10. In addition, the nest 20 includes clip members 38 on opposing lateral sides thereof, which mate with matching clip elements 40 (FIG. 5A) on the base 16 of the test socket 10. The clip members 38 attach the nest 20 to the base 16, but can be manipulated for removing the nest 20 from the base 16.
The nest 20 also includes a sloped alignment surface 42 for aligning the component 12, as it is inserted into the test socket 10. In addition, the nest 20 includes a support surface 44 for supporting the component 12 on the contact plate 26 (FIG. 2B) of the test socket 10. The support surface 44 includes an opening 46 therein which allows the terminal contacts 14 (FIG. 2A) on the component 12 to contact the socket contacts 30 on the base 16.
The nest 20 also includes cut out openings 48 on opposing longitudinal sides thereof, which allow the retention mechanisms 32 (FIGS. 1B and 2B) to move from the loading/unloading position of the test socket 10 (FIG. 2B) to the testing position of the test socket 10 (FIG. 1B). In the testing position of FIG. 1B, the retention mechanisms 32 extend through the openings 48 to hold the component 12 on the contact plate 26. In the loading/unloading position of FIG. 2B, the retention mechanisms 32 retract through the openings 48 to allow the component 12 to be placed on the contact plate 26.
One aspect of the test socket 10 is that the nest 20 cannot be removed without compressing the lid 18, and shifting the test socket 10 to the loading/unloading position of FIG. 2A. FIG. 5A illustrates the base 16 of the test socket 10 in the loading/unloading position with the nest 20 removed. FIG. 5B illustrates the base 16 of the test socket 10 in the testing position with the nest 20 removed. In the testing position the retention mechanism 32 engage portions 50 (FIG. 4) of the support surface 44 of the nest, such that the nest cannot be extracted from the test socket 10.
One problem with having to shift the test socket 10 to the loading/unloading position to remove the nest 20 is that it is difficult to perform in the field with the test socket attached to a burn-in board. Although the nest 20 can be removed in the field, the test socket 10 must often be removed from the burn-in board and transferred to a bench for removing the nest 20. In addition, with the test socket 10 in the loading/unloading position the socket contacts 30 (FIG. 2B) are more susceptible to damage because they are “open” for receiving the terminal contacts 14. It would be desirable to be able to remove and service the nest 20 in the testing position of the test socket 10 (FIG. 1B).
The present invention is directed to a test socket having a nest that can be easily serviced or replaced in the field without shifting the test socket to a loading/unloading position, and without damaging other components of the test socket, such as the socket contacts. In addition, the present invention is directed to a method for testing semiconductor components using the test socket, and to test systems incorporating the test socket.